commit 9bd0c15fcfb42f6245447c53347d65ad9e72080b
author Ben Skeggs <bskeggs@redhat.com> Tue Jun 26 12:12:30 2012 +1000
committer Dave Airlie <airlied@redhat.com> Tue Jun 26 12:16:43 2012 +0100
tree 338d1d19fcb9f76e62ef951b568a8d97a00012ec
parent d42f0349f3fed647c61c2d432e974bbdafcfb3fb

drm/nouveau/fbcon: using nv_two_heads is not a good idea

nv_two_heads() was never meant to be used outside of pre-nv50 code.  The
code checks for >= NV_10 for 2 CRTCs, then downgrades a few specific
chipsets to 1 CRTC based on (pci_device & 0x0ff0).

The breakage example seen is on GTX 560Ti, with a pciid of 0x1200, which
gets detected as an NV20 (0x020x) with 1 CRTC by nv_two_heads(), causing
memory corruption because there's actually 2 CRTCs..

This switches fbcon to use the CRTC count directly from the mode_config
structure, which will also fix the same issue on Kepler boards which have
4 CRTCs.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>